Table I. Transcriptional and functional characterization of the NaCAD gene in wild-type and ir-CAD N. attenuata plants.
Values are means ± se. Asterisks indicate significant differences among the genotypes (unpaired t test: * P < 0.05, *** P < 0.001); n = 5 for quantifying transcript abundance and enzymatic activity analysis, and n = 3 for all lignin analyses. n.d., Not detected.
| Parameter | Sample |
|
|---|---|---|
| GH Wild Type | GH ir-CAD | |
| Gene (transcript abundance %; relative to wild-type; apical stem) | ||
| NaCAD | 100 ± 10.21 | 3.02 ± 0.26*** |
| NaCAD1 | 100 ± 4.82 | 8.96 ± 1.75*** |
| Enzyme (nkat mg−1 protein; apical stem) | ||
| CAD activity | 0.35 ± 0.03 | 0.03 ± 0.01*** |
| SAD activity | 0.36 ± 0.02 | 0.02 ± 0.01*** |
| Lignin composition | ||
| Thioacidolysis-released (β-O-4-linked) monomers (µmol g−1 Klason lignin); basal stem and NMR data | ||
| H units | 26.19 ± 17.71 | 19.45 ± 4.33 |
| G units | 748 ± 28.50 | 390.70 ± 27.43*** |
| S units | 1,152.51 ± 36.48 | 324.21 ± 53.77*** |
| S/G (thio) | 60.6:39.4 | 45.3:54.7 |
| S/G (thio) | 1.54 | 0.83 |
| S/G (NMR) | 43:57 | |
| S/G (NMR) | 0.76 | |
| Coniferaldehyde | n.d. | 4.47 ± 0.70 |
| Sinapaldehyde | n.d. | 31.55 ± 3.16 |
| End group monomers (thioacidolysis) | ||
| Vanillin | n.d. | 7.88 ± 1.05 |
| Syringaldehyde | n.d. | 53.98 ± 3.20 |
| Klason lignin content (%; basal stem) | 21.35 ± 0.51 | 12.13 ± 1.80* |
| Young’s modulus (Gpa; basal stem) | 6.43 ± 0.52 | 2.2 ± 0.25*** |
| Bending strength (Mpa; basal stem) | 2.02 ± 0.08 | 0.9 ± 0.06*** |